Fabric: 0.14.21, BackSlot: 1.2.11, Auto HUD: 4.3, Version: 1.19.2
This mod and Auto HUD seem to be almost compatible, but not completely.

HUD raised

HUD lowered

The HUD slots get hidden, but tools inside them don't.

Ask the AutoHud dev for compatibilty. Might be fixed with the latest version tho.